Abstract: An improved ball grid array (BGA) package having EMI shielding is provided. In a BGA package a thermally conductive heat spreader provided by a conductive layer, and an electrical interconnection is provided between the electrically conductive heat spreader and solder balls of the array, for example by plated through holes extending through the dielectric body of the package. Thus in use of the package, when contacts are made from the array of solder balls to a corresponding array of contact areas of a substrate, a ground connection is simultaneously provided to the heat spreader through the solder balls. For example, one or more conductive contacts on the substrate may be connected to a ground plane of the substrate, and a corresponding solder balls of the package are interconnected to the heat spreader. Beneficially, the ground connection is provided by external rows of solder balls of the array extending around sides of package, or by clusters of solder balls surrounding balls for carrying signals.

Abstract: A package is provided for an integrated circuit comprising a combined heat dissipating and electromagnetic shielding structure. Conveniently, the heat dissipation and shielding structure is a laminated composite structure including layers of several materials having complementary characteristics to provide high magnetic permeability, electrical conductivity, and thermal conductivity. For example, a sandwich structure of layers of copper/Kovar.TM./copper is effective in dissipating heat and reducing electromagnetic emission from ASICs for telecommunications applications, each dissipating in excess of 2 Watts. Preferably a substrate of the package includes a conductive die attach pad which may be grounded to bring a ground plane close to the integrated circuit. The composite electromagnetic shielding and heat dissipation structure is grounded to improve attenuation of radiated electromagnetic emission from the chip.

Abstract: In infrared soldering of components onto circuit boards, where components such as leaded components are first soldered on one surface of a circuit board and then additional components are soldered on the other surface, it is a problem that the solder joints of the first arrangement of components may melt during the second soldering step. Also, heat is reflected from the apparatus and can raise the temperature of components above a defined maximum. In the invention, a heat sink is provided for absorbing heat from the infrared heat source when no circuit board is present, and for absorbing heat from components already soldered, during the second soldering step. Usually the infrared heat source is above the path of the circuit boards and the heat sink is below the path of, and not in contact with, the circuit boards.

Abstract: An integrated circuit is mounted on, and electrically connected to an underlying substrate by the flip-chip technique. In this technique, the chip is inverted and bonding pads on the chip are soldered to correspondingly located bonding pads on the substrate. By the invention a continuous ribbon or loop of solder or polymer extends between the chip and substrate surfaces and defines a sealed cavity. Because the interior of the cavity is sealed from contaminants, conducting leads of the chip or substrate can be left uncovered within the cavity so reducing the capacitance of high frequency circuits. The substrate can be a connection medium such as a printed circuit board or could be another integrated circuit chip.

Abstract: A combined supporting arrangement and RF shield for stacked circuit boards has several conducting shields, each shield covering a respective circuit board and having an edge flange, part of the flange being turned under to space a particular circuit board from the next lower circuit board in the stack, and part of the flange being turned out to engage a clamp projecting from a baseboard, the clamp being common to all the shields.

Abstract: This invention is a structure of, and method of forming, a thin film conductor which crosses either a thin film or thick film glazed circuit underlying structure. A selected low temperature curing insulative dielectric is disposed over a conductor which is to be crossed, and a thin film conductor passes over the dielectric and is in contact with ends of two other conductors, providing a conductive bridge over, and insulated from the underlying conductor.